Polystyrene is a high volume polymer with many uses as a foamed product, as an injected product, and as a copolymer with other materials. Recycle and reuse of polystyrene is limited, however, due to costs of collection, purification, reformation, and reuse versus use of the virgin material. In addition, the slow biodegradation behavior of polystyrene-containing polymers results in high waste disposal costs.
Oxidation of polystyrene to benzoic acid using acetic acid is described in U.S. Pat. No. 6,958,373 to Partenheimer.
It has now been found that waste polystyrene can be efficiently converted to benzoic acid, a commercially useful compound by oxidation at elevated temperature and pressure.